The present invention relates to electrical monitoring systems and methods, and more particularly, but not exclusively, relates to a technique for monitoring electrical power transmission, detecting power transmission anomalies, and selectively collecting data to further analyze such anomalies.
The efficient and reliable distribution of electric power often depends on effective monitoring of the power signals and related equipment to detect anomalous conditions. When an anomalous condition is detected, corresponding data is usually collected for analysis. In many instances, this data is gathered at a number of remote locations for subsequent transmission to a central location for analysis.
One approach has been to store a high resolution digitized waveform of the power signals for a predetermined period of time in response to detection of an anomalous condition. Unfortunately, data storage resources and data transmission rates limit the amount of data that may be collected in this manner. Moreover, the desire to capture data for a rapid succession of anomalous conditions also limits the amount of storage that may be allocated to a given data collection event. Commonly owned U.S. Pat. No. 5,216,621 to Dickens is cited as a source of additional information concerning one waveform storage approach and is hereby incorporated by reference.
In view of the limitations of waveform storage, an alternate approach has been to perform various calculations in real-time and store or transmit the calculation results in place of the waveform data. While storage of results may conserve memory compared to storage of digitized waveform, it also tends to sacrifice information relevant to certain types of anomalies. In still other situations, equipment has been tailored to digitally record a sequence of discrete, power-related events without direct analog signal measurement.
These approaches each fail to offer the type of comprehensive system needed to advance power monitoring performance. Moreover, a system is needed which may be readily reconfigured in response to changing power monitoring needs and still make maximum use of available processing and memory resources. The present invention satisfies these needs and provides other important benefits and advantages.
One form of the present invention is a unique electrical power monitoring system. Another form is a unique method of monitoring one or more electrical parameters.
Other forms of the present invention include techniques to monitor electrical power by generating multiple data streams representative of the same electrical power signal. The multiple data streams uniquely correspond to one or more different performance characteristics and may be supplied at different rates to improve monitoring efficiency.
In still another form of the present invention, an electrical waveform corresponding to an electrical power transmission is sampled to generate a first data stream of waveform samples at a first rate. A second data stream is periodically determined from the first data stream at a second rate slower than the first rate. The second data stream is also representative of the waveform. The first and second data streams may be further processed to selectively form records indicative of power anomalies, disturbances, or other events of interest.
In yet another form, the second data stream is calculated from the first data stream and includes a stream of phasors representative of the waveform. For this form, each phasor corresponds to a predetermined number of the waveform samples. Additional values of interest may be derived from the first or second data streams to add to a given record and/or determine when a record should be generated. By way of nonlimiting example, the determination of when to generate a record may include evaluating the first data stream to trigger a first type of power transmission disturbance and the second data stream to trigger a second type of power transmission disturbance. The record may include at least a prefault portion and a postfault portion of each of the first or second data streams.
Accordingly, it is one object of the present invention to provide a unique technique to monitor electrical power.
Alternatively or additionally, it is another object of the present invention to provide a unique system and method for monitoring electrical power and selectively storing corresponding data.
Further objects, advantages, benefits, aspects, features, and forms of the present invention shall become apparent from the description and drawings herein.